In my own professional work I have touched on a variety
of different fields. I've done my work in mathematical linguistics, for example,
without any professional credentials in mathematics; in this subject I am completely
self-taught, and not very well taught. But I've often been invited by universities
to speak on mathematical linguistics at mathematics seminars and colloquia.
No one has ever asked me whether I have the appropriate credentials to speak
on these subjects; the mathematicians couldn't care less. What they want to
know is what I have to say. No one has ever objected to my right to speak, asking
whether I have a doctor's degree in mathematics, or whether I have taken advanced
courses in the subject. That would never have entered their minds. They want
to know whether I am right or wrong, whether the subject is interesting or not,
whether better approaches are possible - the discussion dealt with the subject,
not with my right to discuss it.

But on the other hand, in discussion or debate concerning social issues or American
foreign policy, Vietnam or the Middle East, for example, the issue is constantly
raised, often with considerable venom. I've repeatedly been challenged on the
grounds of credentials, or asked, what special training do you have that entitles
you to speak of these matters. The assumption is that people like me, who are
outsiders from a professional standpoint, are not entitled to speak on such
things.

Compare mathematics and the political sciences -- it's quite striking. In mathematics,
in physics, people are concerned with what you say, not with your certification.
But in order to speak about social reality, you must have the proper credentials,
particularly if you depart from the accepted framework of thinking. Generally
speaking, it seems fair to say that the richer the intellectual substance of
a field, the less there is a concern for credentials, and the greater is concern
for content.